1. Proposed title of this feature request:
   Enhancements to built-in upgrade strategy in ROSA HCP

a. support upgrading nodes in a rolling window and configurability of how many nodes can be upgraded at once

b. expose maxburst, maxunavailable

1. What is the nature and description of the request?
   enhance upgrade experience for large clusters with support for draining multiple nodes.  this will minimize delays in upgrading overall cluster because a node takes a long time to drain.

e.g. 

Surge upgrades: Nodes are upgraded in a rolling window. You can control how many nodes can be upgraded at once and how disruptive upgrades are to the workloads.   This should also work with maxburst and maxunavailable settings.

3. Why does the customer need this? (List the business requirements here) minimize time to upgrade large scale clusters, avoid getting stuck on nodes that take a long time to drain when using rolling update strategy that updaters one node at a time, move away from current workaround using a blue/green strategy with machinepools, reduce cloud costs with more efficient use of cloud resources, take advantage of simplicity of capi based upgrades  by using a built-in upgrade strategy that works for large clusters and parked nodes

4.  List any affected packages or components.